test(tui): cover the /undo numeric-sequence form (#698 review)

Add a parseCommand("/undo 123") assertion so both the latest and numeric
<sequence> forms of the /rewind contract are exercised through the alias.

internal/cli/exec.go

@@ -939,12 +939,6 @@ func providerSensitiveEnvKeys(resolved config.ResolvedConfig) []string {
 // applyConfiguredSandboxPolicy overlays every config-sourced sandbox knob onto
 // the default policy.
 func applyConfiguredSandboxPolicy(policy sandbox.Policy, cfg config.SandboxConfig) sandbox.Policy {
-	// An explicit `"sandbox": {"enabled": false}` disables the sandbox: every
-	// request is allowed and commands run unwrapped. Only reachable from global
-	// config / CLI — project config never sets Enabled (see mergeProjectConfig).
-	if cfg.Enabled != nil && !*cfg.Enabled {
-		policy.Mode = sandbox.ModeDisabled
-	}
 	if network := strings.TrimSpace(cfg.Network); network != "" {
 		switch sandbox.NetworkMode(network) {
 		case sandbox.NetworkAllow, sandbox.NetworkDeny:

internal/cli/sandbox_test.go

@@ -1001,18 +1001,3 @@ func sandboxPolicyCapabilityStatus(capabilities []sandbox.BackendCapability, key
 	}
 	return ""
 }
-
-func TestApplyConfiguredSandboxPolicyEnabledFalseDisables(t *testing.T) {
-	disabled := false
-	if got := applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), config.SandboxConfig{Enabled: &disabled}); got.Mode != sandbox.ModeDisabled {
-		t.Fatalf("enabled:false must yield ModeDisabled, got %q", got.Mode)
-	}
-	// Omitted (nil) and explicit true keep the default enforcing mode.
-	if got := applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), config.SandboxConfig{}); got.Mode == sandbox.ModeDisabled {
-		t.Fatal("omitted enabled must not disable the sandbox")
-	}
-	enabled := true
-	if got := applyConfiguredSandboxPolicy(sandbox.DefaultPolicy(), config.SandboxConfig{Enabled: &enabled}); got.Mode == sandbox.ModeDisabled {
-		t.Fatal("enabled:true must not disable the sandbox")
-	}
-}

internal/config/resolver.go

@@ -93,16 +93,6 @@ func Resolve(options ResolveOptions) (ResolvedConfig, error) {
 		if err != nil {
 			return ResolvedConfig{}, err
 		}
-		// Sandbox.Enabled is NOT accepted from a provider command, for the same
-		// reason project config cannot set it (see mergeProjectConfig): only
-		// global config and the CLI may turn the sandbox off. A provider command
-		// is an arbitrary executable named in config, and LoadProviderCommand
-		// parses its stdout into a full FileConfig — so without this, a command
-		// returning a valid provider plus {"sandbox":{"enabled":false}} would
-		// disable the very sandbox meant to constrain what it can do. Cleared
-		// here rather than in mergeConfig because that helper is shared with the
-		// trusted global-config merge, which must keep honouring the setting.
-		commandConfig.Sandbox.Enabled = nil
 		mergeConfig(&cfg, commandConfig)
 	}
 
@@ -226,9 +216,6 @@ func mergeConfig(dst *FileConfig, src FileConfig) {
 		mergeProvider(dst, provider)
 	}
 	mergeMCPConfig(&dst.MCP, src.MCP, true)
-	if src.Sandbox.Enabled != nil {
-		dst.Sandbox.Enabled = src.Sandbox.Enabled
-	}
 	if network := strings.TrimSpace(src.Sandbox.Network); network != "" {
 		dst.Sandbox.Network = network
 	}
@@ -286,10 +273,6 @@ func mergeProjectConfig(dst *FileConfig, src FileConfig) error {
 	if err := mergeProjectMCPConfig(&dst.MCP, src.MCP); err != nil {
 		return err
 	}
-	// Sandbox.Enabled is intentionally NOT merged from project config: a cloned
-	// repo's .zero/config.json must not be able to disable the sandbox that
-	// constrains it. Only global config and CLI can turn the sandbox off.
-	//
 	// Sandbox.AdditionalWriteRoots is intentionally NOT merged from project
 	// config: a cloned repo's .zero/config.json must not be able to grant
 	// itself write access outside the workspace. Global config and CLI flags
@@ -705,9 +688,6 @@ func applyOverrides(cfg *FileConfig, overrides Overrides) {
 	if overrides.MaxTurns > 0 {
 		cfg.MaxTurns = overrides.MaxTurns
 	}
-	if overrides.Sandbox.Enabled != nil {
-		cfg.Sandbox.Enabled = overrides.Sandbox.Enabled
-	}
 	if overrides.Sandbox.BlockUnixSockets {
 		cfg.Sandbox.BlockUnixSockets = true
 	}

internal/config/resolver_test.go

@@ -1744,85 +1744,6 @@ func TestResolveSandboxNetworkProjectConfigCannotWeaken(t *testing.T) {
 	}
 }
 
-func TestResolveSandboxEnabledUserConfigDisables(t *testing.T) {
-	userPath := writeConfig(t, `{"sandbox": {"enabled": false}}`)
-	resolved, err := Resolve(ResolveOptions{UserConfigPath: userPath, Env: map[string]string{}})
-	if err != nil {
-		t.Fatalf("Resolve: %v", err)
-	}
-	if resolved.Sandbox.Enabled == nil || *resolved.Sandbox.Enabled {
-		t.Fatalf("user config enabled:false must resolve to a false pointer, got %v", resolved.Sandbox.Enabled)
-	}
-}
-
-func TestResolveSandboxDisableIgnoredFromProjectConfig(t *testing.T) {
-	// Security: a cloned repo's project config must NOT be able to disable the
-	// sandbox that constrains it. Only global config / CLI can turn it off.
-	userPath := writeConfig(t, `{}`)
-	projectPath := writeConfig(t, `{"sandbox": {"enabled": false}}`)
-	resolved, err := Resolve(ResolveOptions{UserConfigPath: userPath, ProjectConfigPath: projectPath, Env: map[string]string{}})
-	if err != nil {
-		t.Fatalf("Resolve: %v", err)
-	}
-	if resolved.Sandbox.Enabled != nil {
-		t.Fatalf("project config enabled:false must be ignored, got %v — a repo could disable the sandbox", *resolved.Sandbox.Enabled)
-	}
-}
-
-func TestResolveSandboxEnabledIgnoredFromProviderCommand(t *testing.T) {
-	// Security: a provider command is an arbitrary executable named in config, and
-	// its stdout is parsed into a full FileConfig — so it must NOT be able to reach
-	// Sandbox.Enabled, in either direction. Same rule as project config: only global
-	// config / CLI may turn the sandbox off.
-	for _, tc := range []struct {
-		name  string
-		value string
-	}{
-		{name: "cannot disable", value: "false"},
-		{name: "cannot enable", value: "true"},
-	} {
-		t.Run(tc.name, func(t *testing.T) {
-			command := writeCommand(t, commandScript{
-				Stdout: `{"activeProvider":"cmd","providers":[{"name":"cmd","provider":"openai","apiKey":"sk-command","model":"gpt-command"}],"sandbox":{"enabled":` + tc.value + `}}`,
-			})
-			resolved, err := Resolve(ResolveOptions{ProviderCommand: command, Env: map[string]string{}})
-			if err != nil {
-				t.Fatalf("Resolve: %v", err)
-			}
-			// The provider itself must still be applied — only the sandbox toggle is dropped.
-			if resolved.ActiveProvider != "cmd" {
-				t.Fatalf("ActiveProvider = %q, want cmd (provider command must still apply)", resolved.ActiveProvider)
-			}
-			if resolved.Sandbox.Enabled != nil {
-				t.Fatalf("provider command set sandbox.enabled=%s, got %v — a provider command could toggle the sandbox", tc.value, *resolved.Sandbox.Enabled)
-			}
-		})
-	}
-}
-
-func TestResolveSandboxEnabledCLIOverride(t *testing.T) {
-	// A CLI/programmatic override (applied after every config source) must be able
-	// to disable the sandbox, even with no config file.
-	disabled := false
-	resolved, err := Resolve(ResolveOptions{Env: map[string]string{}, Overrides: Overrides{Sandbox: SandboxConfig{Enabled: &disabled}}})
-	if err != nil {
-		t.Fatalf("Resolve: %v", err)
-	}
-	if resolved.Sandbox.Enabled == nil || *resolved.Sandbox.Enabled {
-		t.Fatalf("CLI override enabled:false must disable the sandbox, got %v", resolved.Sandbox.Enabled)
-	}
-	// An explicit true override must win over a lower-precedence global-config false.
-	userPath := writeConfig(t, `{"sandbox": {"enabled": false}}`)
-	enabled := true
-	resolved2, err := Resolve(ResolveOptions{UserConfigPath: userPath, Env: map[string]string{}, Overrides: Overrides{Sandbox: SandboxConfig{Enabled: &enabled}}})
-	if err != nil {
-		t.Fatalf("Resolve: %v", err)
-	}
-	if resolved2.Sandbox.Enabled == nil || !*resolved2.Sandbox.Enabled {
-		t.Fatalf("CLI override enabled:true must win over config false, got %v", resolved2.Sandbox.Enabled)
-	}
-}
-
 func TestResolveNotifyValid(t *testing.T) {
 	path := writeConfig(t, `{"notify":{"mode":"both","focusMode":"always"}}`)
 	resolved, err := Resolve(ResolveOptions{UserConfigPath: path, Env: map[string]string{}})

internal/config/types.go

@@ -62,12 +62,6 @@ func HasProviderProfile(profile ProviderProfile) bool {
 }
 
 type SandboxConfig struct {
-	// Enabled turns the sandbox off when set to false (`"sandbox": {"enabled":
-	// false}`). A pointer distinguishes an explicit false (disable) from an
-	// omitted key (keep the default: enabled). Honored from the GLOBAL user
-	// config and CLI only — deliberately NOT project config, so a cloned repo
-	// cannot disable the sandbox that constrains it. nil / true keep enforcement.
-	Enabled *bool `json:"enabled,omitempty"`
 	// Network controls whether shell commands classified as network-touching
 	// (curl, git push, package installs, …) are allowed: "allow" or "deny".
 	// Empty keeps the built-in default (deny). Without this knob the engine's

internal/tui/commands.go

@@ -253,6 +253,7 @@ var commandDefinitions = []commandDefinition{
 	},
 	{
 		name:        "/rewind",
+		aliases:     []string{"/undo"},
 		usage:       "/rewind [latest|<sequence>]",
 		group:       commandGroupSession,
 		description: "Restore workspace files to a checkpoint and truncate the session.",

internal/tui/commands_test.go

@@ -985,6 +985,31 @@ func TestParseBackgroundTerminalCommands(t *testing.T) {
 	}
 }
 
+// /undo is an alias for /rewind (issue #698): previously it fell through to
+// commandUnknown.
+func TestUndoAliasesRewind(t *testing.T) {
+	rewind, ok := resolveCommand("/rewind")
+	if !ok {
+		t.Fatal("expected /rewind to resolve")
+	}
+	alias, ok := resolveCommand("/undo")
+	if !ok || alias.kind != rewind.kind {
+		t.Fatalf("expected /undo to alias /rewind, got ok=%v command=%#v", ok, alias)
+	}
+	// End-to-end: a typed /undo dispatches to the rewind handler with args intact,
+	// for both the "latest" and numeric-<sequence> forms of the /rewind contract.
+	if parsed := parseCommand("/undo latest"); parsed.kind != commandRewind || parsed.text != "latest" {
+		t.Fatalf("parseCommand(%q) = %#v, want commandRewind with text=latest", "/undo latest", parsed)
+	}
+	if parsed := parseCommand("/undo 123"); parsed.kind != commandRewind || parsed.text != "123" {
+		t.Fatalf("parseCommand(%q) = %#v, want commandRewind with text=123", "/undo 123", parsed)
+	}
+	// Guard: without the alias it would be commandUnknown.
+	if parsed := parseCommand("/undo"); parsed.kind == commandUnknown {
+		t.Fatal("/undo resolved to commandUnknown — the alias is not wired")
+	}
+}
+
 func TestCommandSelectionRequiresInputFromUsage(t *testing.T) {
 	cases := []struct {
 		name string